Hydraulic accumulator.



A. W. FRENCH.

HYDRAULIC ADGUMULATOR.

APPLIUATION FILED 11.23, 1905.

Patented Nov. 30, 1909.

2 SKBETSSHEBT 1.

1T TU w i A. w. FRENCH.

HYDRAULIC AGUUMULATOR. APPLICATION FILED APR.Z3,1908.

941 ,867. Patented Nov. 30. 1909.

2 SHEETSSHEET 2.

mil 0 7on2 5.9.

Wfnessesr ALFRED w. marten, or emu, omo.

HYDRAULIC AOOUHULA'IOB.

Specification of Letters Patent.

Patented Nov. 30, 1909.

Application fled April 88, 1808. Serial 110. 428,858.

To all whom it may concern:

Be it known that I, Aer-nae W. Fanncn, a citizen of the United States, residmg at Pique, in the county of Miami and State of Ohio, have invented a new and useful Improvement in Hydraulic Accumuletors, of which the followmg is a specification.

This invention relates to automatic hydraulic accumulators of the sort that are emplo ed in connection with presses and other ydraulic machines for storing the opcrating liquid usually oil) under pressure to supplement e pum s or other source of supp y in furinishing o to the presses when required. These accumulators are provided with relief valves which allow the oil to pass from the pum or other source of supply to the accum star and presses until a predetermined desired quantity of oil is stored in the accumulator, when t e relief valve is automatically operated to open a by-pass which allows the oil to pass back to the pumps or storage tank, or to circulate freely, so as to relieve the umps from work.

The princi al ob ect of the invent-ion is to produce a re ief valve mechanism for this purpose of ver simple and Inexpensive construction whic requires little or no ad ustment and will not readily get out of order and which operates to qulckl open and close the relief valve to the ful extent and, when once opened to relieve the pumps, to hold it wide open during a considerable travel of the movable piston or part of the accumulator, so that the valve Wlll not fluctaste and cause repeated sudden changes of load on the pumps, which results in pounding and wearing the valve and racking and straining the umps.

Another ob ect of the invention is to improve the oonstruction of the accumulator cylinder as hereinafter described and set forth in the claims.

in the accom anying drawings, consisting of two sheets: igure 1 is a sectional cleva (ion of an automatic hydraulic accumulator embodying the invention. Fi 2 is a sectional elevation on an enlarge scale in line 2-2, Fig. 5, of the relief valve. Eig. 3 is :1 similar view, on a smaller scale, showing the valve open and also showing the o wrutivo connections between the valve no the accumulator. Fig. 4 is a transverse soclional elevation of the relief valve in line 4 4, Fi 2. Fig. 5 is n Ian view of the relief vn vo. Fig. 6 is u l rngmontary sol-.-

rlower heads a a.

llzionalL plan of the accumulator, in line 6-45,

e letters of reference refer to like parts in the several figures.

The accumulator, as usual, consists of an u prifiht pressure cylinder A to the lower end 0 w ich the oil is admitted under pressure from the pumps or other source of supply; a piston or lunger B arra' to move ver' tically in t e cylinder; an a weight tank or rece tacle C which is hung from the upper en of the piston and contains weights or loading the plunger to produce the necessary pressure 111 the accumulator.

The pressure cylinder A can be of any suitable construction but is preferably constructed as shown in Fig. 1, consisting of an inner steel tube or cylinder a he screwthreaded connections at its ends wi upper and lower heads a a, and an outer cast iron tube a, the opposite ends of which surround and are securely bolted to the upper and The w ht tank-consists of inner and outer cy udrical sheet metal wells suitably secured to the inner and outer rims of an annular bottom 0' which surrounds the pressure cylinder and is suspended by rods or bolts 0' from a cross head 0 at the upper end of the piston B. The outer tube a of the pressure cylinder is cast w th external lon tudinal guide ribs d, Figs. 1 and 6, whic enter guide notches d in the bottom of the weight tank and act to guide the tank and prevent it from turning and tilting.

The described construction of the pressure cylinder is very desirable for high pressure accumulators. The cylinder is much li hter than a single-piece cast iron cylinder 0 the requisite strength, and the inner steel tube which carries the pressure reaching four thousand pounds or more per square inch, is much more reliable than the heavier cast Iron cylinder which is apt to be spon E represents the casing of the relie alve. Oil from the pumps, or other source of supply, enters a main passage a of the valve casing by n pi e c and passes therefrom by a plpfl c to t 1e nccumu ntor and by a pipe 0 to the presses or other machines where the oil is used.

a is a hy-pass passage connecting the main passage 0 with a pipe c" loading lmclr to the storage tank or to t m pumps.

F represents the relief valve. and f a soul. therefor at the juncture of lho main and byass passages e e of the casing. The valve ms an enlarged guide portion in one side of which is located a groove f for permitting the oil to pass above this enlarged portion in order that the pressure will tend to keep the valve on its seat. When this valve is seated it closes the by-pass and the oil will pass to the accumulator and preses, if the latter are taking oil, while by unseatin the valve the by-pass e is opened, which a owe the oil to circulate back to the pumps or stora e tank through the b -pass and relieve the end on the pumps. reciprocating plunger valve is shown having a stem f projecting from the valve casing and connected to an operating lever G by a pin 9 entering a slot g in the lever. This pin and slot, or loose connection, between the valve and lever allows the lever, which is connected to the movable piston or art of the accumulator, to move 1n either direction with said piston or art, a distance depending u on the length 0 the slot, before actuating t e valve and to then quickly and com letely open or close the valve. A spring surroundin the stem of the relief valve between a co lar or part thereon and the valve ca assists in openin the valve and holding 1t open. The re- Iie valve could be of other construction and have a different sort of loose connection with its cperatin lever, but the construction shown is pre erred.

I represents a vertical 0 eratin rod connected to the free end 0 the re ief valve lever and extending up through a rforated guide I or bracket 1' on the mova le weight tank of e accumulator and provided at its upper end with a head or enlargement i. A coil spring K loosely surrounds this rod,

resting upon the lug or bracket 1' and is adapted to ascend and descend with the weight tank.

L represents a check valve of any suitable kind arranged in the main pasage e between the relief valve and the connections e e to the accumulator and presses to hold the pressure therein when the relief valve is 0 en.

The operation of the device is as follows: When the relief valve F is seated or closed as shown in Fig. 2, the oil from the pumps will flow to the accumulator cylinder A y the pi e e and raise the piston B and weight tank and if the resses or other machines are in operation the oil will also pass to these by the pi e a. When the spring K which rises wit] the tank, on l as the earl of the operating rod I it wil lift the some and the relief valve lever t}, the slotted connection between the lever and valve permittin; the lever to move independently of the va vo until the lower end of its slot ongages the pin on the valve atom. The spring .IB COIIKIPI'DSSlMl by the wclght of the valve lover an rod I and the resistance to the opening of the valve until it exerts sutlicient power to overcome these op sing forces, when the spring will sudden y ex and and open the relief valve F to its fu l extent. '1 1e spring H surrounding the stem of the relief valve assists in quickly 0 coin the valve. The oil can then circulhte me] back to the pumps or storage tank throu h the openly-pass (passe e. The weight tank Wlll desccn as on is drawn from the accumulator, thus allowing the relief valve lever G and rod I to descend by reason of their weight. The relief valve will, however, be held up, or o n, by the pressure of the oil thereon assist b the sprm H until the upper end of the s ot in the ever ongages the pin on the valve stem, when the weight of the lever and rod will quickly close or seat the valve. Thus the slotted or loose connection between the relief valve and its operatuzlg lever permit the valve to remain close during the ascent of the accumulator piston and to be then suddenly o ned when the pressure cylinder has been filed to the desired height, and to remain open until a considerable quantity of oil has been drawn from the ressure cylinder and the iston allowed to \ihscend some distance, so t at the valve does not respond to short movements of the accumulator piston caused bly sli ht fluctuations in volume of the oil in t e cy inder. The valve, therefore, will not be opened and closed at short intervals whic would cause it to ound and wear and produce rapid changes 0 load on the pum resulting In severe strains thereon. Thi s distance which the relief valve lever is permitted to move with the accumulator piston independently of t valve is dependent ugaon the length of t e slot in the lever and t is can be made of the proper length to give the desired results. The parts of t 1e relef valve mechanism are few in number and simple in construction, and there are no parts requiring adjustment and liable to get out of order.

I claim as my invention:

1. The combination of an accumulator having a part moved by the liquid pressure, a supply passage connecting the accumulator with a source of sup 1 a by-pass passa 'e connecting with saul supply passage ietween the source of supply and the accumulator, a relief valve for opening and closin I said by-pass passage, and an 0 )crnting evice for said valve which has a 0st motion connection with said relief valve which allows a limited movement of the operating device independently of the valve in both the valve opening and valve closing movements of the operating device, and connections between the movable part of the uccomulatmgand said valve operating device which allows a prmlolormincd movamcut of the movable part of tho accumulatinbefore it actuates said valve operating device, substantially as set forth.

2. The combination of an accumulator having a part moved by 11 md presnre, a supply passage connecting t e accumulator wit a source of supply, a by-pass go connecting the said sup ly passage tween the source of supply an the accumulator, a relief valve for opening and closing said bypam passa e, an operating device for said valve whi has a lost motion connection with said relief valve which allows 9. limited movement of the operating device independently of the valve, and connections between the movable part of the accumulator and said valve operating device which allows a predetermined movement of the movable part of the accumulator before it actuates said valve operating device, and a chesk bvalve between ti? accumulator atfig sai y-pass p or preventm escape of li uid em the accumfilator through said y-pass passage, substantially as set forth.

3. The combination of an accumulator having a part moved by the liquid pressure, a supply passage for said accumulator, a b pass passage connecting with said supp y passage, a relief valve for opening and c osing said by-pass passage, on o crating lever for said valve which is actuatci i by the movable part of said accumulator and has a loose connection with said relief valve which allows a predetermined movement of the lever independently of the valve, and a spring which acts on said valve independently of said lever in a direction to open said by-pass passage, substantially as set forth.

4. The combination of an accumulator having a part moved by the liquid pressure, a. supply passage for said accumulator, a b pass passage connecting with said sup y passage, a reciprocating relief valve or o ening and closi said by-pass assa a5 operating lever or said valve v hich iii actuated by the movable art of said accumulator and has a slotte connection with said relief valve which allows a predetermined movement of the lever independently of the valve, and a spr' which acts on said relief valve independent y of said lever in a direction to lifilen said by-pass, substantially as set to 5. The combination of an accumulator having a part moved by the liquid pressure, a relief valve casin havin a supply passage for the accum ator an a by-pass passa connecting therewith, a reciprocating va ve controlling said by-pass passage having a stem projecting out of said casing, a spring acting on sai valve stem in a direction to move said valve to open said bypass passage and an operating lever for said valve which is actuated b the movable part of the accumulator and as a slotted connection with said valve stem which allows a predetermined movement of the lever independently of the valve, substantially as set forth.

6. In an accumulator, the combination of an inner steel cylinder tube heads screwed on the opposite ends of said tube, an outer cast iron tube having its opposite ends fitting and secured to portions of said heads sai moi outer tube having integral exte guide ribs extending longitudinally thereof, a piston working in said cylinder, and a weight tank surrounding said cylinder and having notches in which said guide ribs eng'a substantially as set forth.

itness my hand, this 13th day of April, 1908.

ALFRED W. FRENCH.

Witnesses:

Cline. C. Wamnnan, E. R. IIARRIS. 

